Dryer feed nozzle assembly

ABSTRACT

A feed assembly for fluid energy type mills wherein dispersions of granular material or solutions are fed through a nozzle and are entrained in tangentially directed jets of gaseous fluid which create a vortex in front of the jet nozzle and atomize or aspirate the wet particles. A vacuum which is formed between the tip of the feed nozzle and the vortex is broken and which thereby creates a suction to pull particles back against the nozzle tip, causing abrasion, is broken by the insertion of low pressure gaseous fluid between the vortex and the nozzle tip.

United States Patent [191 Stephanoff June 4, 1974 DRYER FEED NOZZLE ASSEMBLY [75] Inventor: Nicholas N. Stephanoff, Haverford,

[73] Assignee: Fluid Energy Processing &

Equipment Company, Hatfield, Pa.

[22] Filed: June 18, 1973 [21] Appl. No.: 370,985

[52] US. Cl 239/8, 34/10, 239/405 [51] Int. Cl.....' F26b 3/08, B05b 1/34 [58] Field of Search 239/398, 399, 400, 403,

239/405, 8, 428; 34/57 E, 10, 58,57 R, 57 B;

[5 6] References Cited UNITED STATES PATENTS Weiss 302/5] UX Stephanoff 34/l0 l/l933 9/l967 3,667,13! 6/1972 Stephanoff 34 10 Primary Examiner-M. Henson Wood, Jr.

Assistant ExaminerMichael Y. Mar Attorney, Agent, or FirmArthur A. Jacobs, Esq.

57 ABSTRACT A feed assembly for fluid energy type mills wherein dispersions of granular material or solutions are fed through a nozzle and are entrained in tangentially directed jets of gaseous fluid which create a vortex in front of the jet nozzle and atomize or aspirate the wet particles. A vacuum which is formed between the tip of the feed nozzle and the vortex is broken and which thereby creates a suction to pull particles back against the nozzle tip, causing abrasion, is broken by the insertion'of low pressure gaseous fluid between the vortex and the nozzle tip.

8 Claims, 3 Drawing Figures PATENTEBJUH 4:974 Y 31814316 SHEEI 2 BF 2 FIG. 3

This invention relates to feed nozzles for fluid energy drying mills, and it particularly relates to nozzles of this type which are protected against abrasive deterioration.

Fluid energy drying mills are briefly described as tubular housings having a substantially linear inlet chamber contiguous to an annular chamber. Wet material, such as a slurry or a solution, to be dried is propelled through a feed nozzle into the inlet chamber and is entrained by a hot gaseous fluid, such as air, steam or other desirable gaseous fluids, which enters the inlet chamber tangentially to the direction of the feed. The fed material is atomized at the feed inlet and immediately begins to be dried by the hot gas which, at the same time, carries the particles resulting from the atomized dispersion or solution into the annular chamber where the particles are subjected to centrifugal action.

The particles are initially of varying sizes and, when the liquid is at least partially removed by drying, the adhesion between the particles due to the liquid, is re moved so that the now discrete particles are relatively free to move under the action of the centrifugal forces in accordance with their own particular size and weight. The heavier particles move through the annular chamber on the outer periphery and the finer or lighter particles move on the inner periphery. An exhaust duct is provided adjacent the inner periphery of the annular chamber and the lighter particles exhaust therethrough as they pass around the annular chamber, whereas the heavier particles pass through the mill.

Since the heavier particles are either those which have a larger surface area and are, therefore, not as rapidly dried as the smaller particles with less surface area, or are those which have, for some other reason, not been completely dried and, therefore, carry the additional weight of the adherent liquid, or are actually two or more particles which are still coagulated together because the liquid adhesive between them has not yet been affected by the drying gases, they centrifugally recycle through the mill until completely dried and separated, at which time they pass through the inner periphery of the mill into the exhaust duct.

The above described fluid energy drying mill is generally of standard construction and, by itself, forms no part of the present invention. The present invention relates specifically to the feed means for the material to be processed.

The feed means generally used for this type of mill normally comprises a feed nozzle placed at the free end of the inlet chamber and arranged to project the material axially of the inlet chamber. This nozzle is connected to a source of the material and the material is pumped through the nozzle. Adjacent the outlet end of the feed nozzle are atomizing nozzleswhich expel high pressure, high velocity gaseous fluid into the linear path of the material as it exits from the feed nozzle. There are generally a plurality of such atomizing nozzles arranged tangentially to each other and the feed nozzle so that when the material leaves the feed nozzle it is immediately entrained, atomized and propelled forwardly through the inlet chamber by the high energy fluid jet streams. V

The above atomizing and feed action causes a partial vacuum to develop behind the atomizing nozzles. The

resulting suction tends to pull back some of the now atomized material which thereupon impact against the tip of the feed nozzle. The result is rapid, deleterious wear of the nozzle tip due to the abrasive impacts. This necessitates frequent nozzle replacement. resulting in undesirable shut-down of the mill and undue expense.

It is an object of the present invention to overcome the aforesaid problem by providing a feed nozzle assembly which is adapted to operate with undiminished effectiveness but which is not subject to undue wear because of abrasive action of the fed particles.

Another object of the present invention is to provide a feed nozzle assembly of the aforesaid type which is relatively simple in construction and is not materially more expensive to construct and use than prior nozzle assemblies of this type.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following description when read in conjunction with the accompanying drawings wherein:

FIG. 1 is a side view, partly in section and partly in elevation,-of a fluid energy drying mill equipped with a feed nozzle assembly embodying the present inventron.

FIG. 2 is an enlarged, detailed sectional view of the feed nozzle assembly of FIG. 1.

FIG. 3 is a sectional view taken on line 3-3 of FIG. 2.

Referring now in greater detail to the various figures of the drawings, there is shown in FIG. 1 a drying mill, generally designated 10, having an inlet chamber 12 and an annular section 14. The section 14 comprises an upstack portion 16, a classifier section 18 and a downstack portion 20. An exhaust outlet 22 is provided at the inner periphery at the unction of the classifier and downstack portions, this outlet leading to an exhaust duct 24.

The inlet chamber 12 is provided with a plurality of tangential nozzles 26 which are in fluid connection with a manifold or the like 28 having a supply of heated gaseous fluid under pressure, such as air, superheated steam, nitrogen, or similar gaseous materials.

, At the free end of the inlet chamber 12 is a feed nozzle assembly generally designated 30. This feed nozzle assembly 30 is shown in detail in FIGS. 2 and 3 and comprises an inlet nozzle 32 connected to a conduit 34 by a connection 36. The conduit 36 is connected to a source of material to be processed which is fed through the conduit 36 by any desired means, such as a pump or the like. The material to be processed is generally in the form of a liquid slurry of dispersed solid particles, but may also be in the form of a solution.

The nozzle 32 is positioned within an annular fitting 38 attached to the open free end of the chamber 12, and this fitting is provided with an annular chamber 40. The chamber 40 is supplied with pressurized gaseous fluid by a duct 42 connected to an inlet 44. The duct 44 is connected to a source of gaseous fluid under pressure, not shown.

In fluid communication with chamber 40 are a plurality of nozzles 46. These nozzles 46 extend inwardly toward the axial plane of the nozzle 32 but the points of intersection of the fluid streams from the nozzles 46 are spaced forwardly of the tip of the nozzle 32. In addition, the nozzles 46 are so arranged that the gaseous streams issuing therefrom are substantially tangential to the stream issuing from the nozzle 32. These tangential gaseous streams form a vortex'into which the slurry or solution from nozzle 32 is propelled the vortex acting to atomize or aspirate the fed material while, at the same time, propelling the particles forwardly into the inlet chamber 12 because of the forwardly-inclined direction of the nozzles 46.

Normally, as the result of the high velocity, high pressure streams or jets which issue from the nozzles 46 and create the vortex in front of the nozzle 32, at least a partial vacuum condition is formed behind the vortex.

This vacuum or suction acts to draw back some of the particles from the slurry and causes them to abrasively impact against the tip of the nozzle 32, resulting in rapid wear of the nozzle tip. 7

In accordance with the present invention, the suction caused abrasive action is eliminated by providinga spaced concentric sleeve 48 around the nozzle 32. This sleeve 48 may either be open to the atmosphere or it may be connected to a source of low pressure gaseous fluid, such as air, nitrogen, or the like, not shown, through a duct such as shown at 50.

The flow of the low pressure air or other. gaseous substance through sleeve 48 acts to break the vacuum formed behind the vortex, and, thereby, prevents the abrasive backward movement of the fed particles.

The invention claimed is:

l. A drying mill comprising an inlet chamber in communication with an annular chamber having an upstacked section, a classification section and a downstack section, said upstack sectionleading from one end of said inlet chamber and said downstack section leading back into said inlet chamber, said classification section being between said upstack and downstack sections, at least one gaseous fluid inlet means leading into said inlet chamber, said gaseous fluid inlet means being arranged tangentially to saidinlet chamber and being inclined toward said one end of said inlet chamber, a feed assembly at the opposite end of said inlet chamber, said feed assembly comprising a feed nozzle connected to a source of wet material, to be treated, said feed nozzle and the area of impact between said stream of atomizing gaseous fluid and said material.

2. The mill of claim 1 wherein there are a plurality of atomizing nozzles in annular arrangement forwardly of the outlet end of said feed nozzle, said atomizing nozzles being inclined away from the outlet end of said feed nozzle and being constructed and arranged to project streams of gaseous fluid tangentially toward impact with said material. a

3. The mill of claim 1 wherein said suction-breaking means comprises a sleeve concentric with but spaced from said feed nozzle, said sleeve being in communication with a source gaseous fluid. v

4. A feed nozzle assembly for wet material comprising a feed nozzle connected to a source of said wet material, said feed nozzle being constructed and arranged to propel said material into said opposite. end of said inlet chamber, at least one atomizing nozzle constructed and arranged to project a stream of atomizing gaseous fluid tangentially toward impact with said material as said material is propelled from said feed nozzle, and suction-breaking means constructed and arranged to insert a mass of gaseous fluid between the outlet end of said feed nozzle and the area of impact between said stream of atomizing gaseous fluid and said material.

5. The assembly of claim 4 wherein there are a plurality of atomizing nozzles in annular arrangement forwardly of the outlet end of said feed nozzle, said atomizing nozzles being inclined away from the outlet end of said feed nozzle and being constructed and arranged to project streams of gaseous fluid tangentially toward impact with said material.

6. The assembly of claim 4 wherein said suctionbreaking means comprises asleeve concentric with but spaced from said feed nozzle, said sleeve being in communication with a source gaseous fluid.

7. A method of feeding wet material into a mill-which comprises propelling the material through a feed nozzle, atomizing said material forwardly of the feed nozzle by projecting at least one stream of atomizing gaseous fluid tangentially against the material as it leaves feed nozzle being constructed and arranged to propel said material into said opposite end of said inlet chamber, at least one atomizing nozzle constructed and arranged to project a stream of atomizing gaseous fluid tangentially toward impact with said material as said material is propelled from'said feed nozzle, and suction-breaking means constructed and arranged to insert a mass of gaseous fluid between theoutlet end of said the feed nozzle, and preventing suction behind the area of impact between said atomizing fluid and said material by inserting a gaseous fluid between said area of impact and the outlet end of the feed nozzle.

8. The method of claim 7 wherein there are a plurality of streams of atomizing gaseous fluid projected tangentially toward said material.

i in a; 

1. A drying mill comprising an inlet chamber in communication with an annular chamber having an upstacked section, a classification section and a downstack section, said upstack section leading from one end of said inlet chamber and said downstack section leading back into said inlet chamber, said classification section being between said upstack and downstack sections, at least one gaseous fluid inlet means leading into said inlet chamber, said gaseous fluid inlet means being arranged tangentially to said inlet chamber and being inclined toward said one end of said inlet chamber, a feed assembly at the opposite end of said inlet chamber, said feed assembly comprising a feed nozzle connected to a source of wet material, to be treated, said feed nozzle being constructed and arranged to propel said material into said opposite end of said inlet chamber, at least one atomizing nozzle constructed and arranged to project a stream of atomizing gaseous fluid tangentially toward impact with said material as said material is propelled from said feed nozzle, and suction-breaking means constructed and arranged to insert a mass of gaseous fluid between the outlet end of said feed nozzle and the area of impact between said stream of atomizing gaseous fluid and said material.
 2. The mill of claim 1 wherein there are a plurality of atomizing nozzles in annular arrangement forwardly of the outlet end of said feed nozzle, said atomizing nozzles being inclined away from the outlet end of said feed nozzle and being constructed and arranged to project streams of gaseous fluid tangentially toward impact with said material.
 3. The mill of claim 1 wherein said suction-breaking means comprises a sleeve concentric with but spaced from said feed nozzle, said sleeve being in communication with a source gaseous fluid.
 4. A feed nozzle assembly for wet material comprising a feed nozzle connected to a source of said wet material, said feed nozzle being constructed and arranged to propel said material into said opposite end of said inlet chamber, at least one atomizing nozzle constructed and arranged to project a stream of atomizing gaseous fluid tangentially toward impact with said material as said material is propelled from said feed nozzle, and suction-breaking means constructed and arranged to insert a mass of gaseous fluid between the outlet end of said feed nozzle and the area of impact between said stream of atomizing gaseous fluid and said material.
 5. The assembly of claim 4 wherein there are a plurality of atomizing nozzles in annular arrangement forwardly of the outlet end of said feed nozzle, said atomizing nozzles being inclined away from the outlet end of said feed nozzle and being constructed and arranged to project streams of gaseous fluid tangentially toward impact with said material.
 6. The assembly of claim 4 wherein said suction-breaking means comprises a sleeve concentric with but spaced from said feed nozzle, said sleeve being in communication with a source gaseous fluid.
 7. A method of feeding wet material into a mill which comprises propelling the material through a feed nozzle, atomizing said material forwardly of the feed nozzle by projecting at least one stream of atomizing gaseous fluid tangentially against the material as it leaves the feed nozzle, and preventing suction behind the area of impact between said atomizing fluid and said material by inserting a gaseous fluid between said area of impact and the outlet end of the feed nozzle.
 8. The method of claim 7 wherein there are a plurality of streams of atomizing gaseous fluid projected tangentially toward said material. 